1. Field of the Invention
This invention relates to a locking assembly. More particularly, this invention relates to a locking assembly for a toolholder to releasably secure the toolholder with a tool support member.
2. Description of the Related Art
The present invention relates to a locking assembly for a toolholder for releasably holding tools with respect to a tool support member and a method of using the locking assembly.
The present invention is especially concerned with toolholders and support members wherein the support member has a bore for receiving the shank of the toolholder and the toolholder has a cutting insert seat on its forward end. Such articles are used in the cutting and shaping of workpieces where it is important that the toolholder be held by the tool support member in a rigid manner so that both movement and vibration are minimized during the metalcutting operation.
Many devices in the prior art have proven to be successful in this regard and are exemplified by McCreery U.S. Pat. No. 3,498,653; McCray et al. U.S. Pat. No. 4,135,418; Heaton et al. U.S. Pat. No. 4,197,771; and Friedline U.S. Pat. No. 4,350,463; incorporated herein by reference. The foregoing devices are concerned with the use of ball-like locking elements to hold the shank of a toolholder in the bore of the tool support member.
Although the prior art devices have been proven to perform satisfactorily, it will be appreciated that there is always a need for improved locking assemblies for toolholders, support members that provide an acceptable degree of rigidity during metal cutting operations such that a single assembly of toolholder, support member and locking members can be used in the widest possible variety of machining operations to provide a given surface finish in a heavier cut or a finer surface finish for a given depth of cut and feed rate.
Briefly, according to this invention, there is provided a locking assembly for a toolholder to releasably secure the toolholder with a tool support member and a combination of a locking assembly, toolholder and tool support member and a method of using the locking assembly, toolholder and tool support member.
The locking assembly includes a wedge screw including a generally longitudinally extending member having a threaded first end second end and a projection between the first and second end and extending from the member, wherein the first end is threaded in a direction opposite of the threads of the second end and wherein the number of threads per inch varies between the first end and the second end of the wedge screw; the wedge screw and a wedge member adapted to threadably engage each of the first and second end of the wedge screw, wherein the wedge members are rotatably fixed and axially movable along the wedge screw a controlled distance between a first position wherein the toolholder is locked with respect to the tool support member and a second position wherein the toolholder is released from the tool support member.
The toolholder includes a forward end, abutment face and a shank adjacent to and connected to the abutment face and extending rearwardly from the forward end. The shank includes a first section and a second section, wherein the second section is perforated by a first and a second perforation that are circumferentially spaced from each other and have a slot extending rearwardly of each of the perforations. The first and second perforations contain a lockable perforation having a lockable surface.
The tool support member includes a sidewall, a forwardly facing surface, a rearwardly facing surface, and a bore adapted to receive the shank of the toolholder, and a passageway in communication with the bore extending through the sidewall of the tool support member for receiving the locking assembly. The forwardly facing surface is engageable with the abutment face of the toolholder.
The method of locking and releasing a toolholder with respect to a tool support member using a locking assembly wherein the toolholder is locked with respect to the tool support member in a first position and the toolholder is released from the tool support member in a second position includes the steps of locking the toolholder with respect to the tool support member in the first position by threading the wedge screw into the wedge members thereby drawing the wedge members radially inwardly such that the wedge members contact the lockable surface around the lockable perforation within the shank of the toolholder thereby, and releasing the toolholder with respect to the tool support member in the second position by withdrawing the wedge screw from the wedge members and forcing the wedge members to move outwardly in opposite directions thereby unlocking the toolholder from the tool support member whereby the wedge members travel outwardly along the wedge screw within the passageway at different rates.